Socket for twist-drills



(No Medal.) y

' G. A. LETTER.

SOCKET FOR TWIST DRILLS.

No. 321,615. Patented July 7,1885.

UNITED STATES PATENT @rrtcn.

GEORGE ALBERT LETTER, OF CHICAGO, ILLINOIS.

SOCKET FOR TWlST=DRlLLS.

SPECIFICATIQN forming part of Letters Patent No. 321,615, dated July 7,1885.

Application filed April 4, 1885.

To all whom it may concern.-

Be it known that I, GEORGE A. LETTER, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a new and useful Improvement in the Sockets forHoldingIwist-Drills, of which the following is a specification.

The object of my invention is to provide a fastening for drills indrill-sockets when the keeper is broken off the drill. I attain thisobject by the mechanism illustrated in the accompanying drawings, inwhich-- Figure 1 is an elevation. Fig. 2 is a vertical section of Fig.1, taken through x as. Fig. 3 is a crosssection of Fig. 1, showing amodification of my invention.

Fig. 1 shows a drill socket with a drill inserted therein. In the lowerpart of the drill-socket I mill out a space suiiiciently long and wideto admit a key, a. This opening passes through the socket to theholeoccupied by the drill B. The key is held in position by a pin, 6, asshown in the drawings, and it passes through the solid portion of thesocket and forms a pivoting-point for the key. The holefin the key ismade as shown in Fig. 2. This allows the key to fall into position atboth ends alike. The lower end of the key 0 is rounded on the inneredge, so that when the drill enters the socket and strikes the end ofthe key it will pass under the key and allow it to go to its place inthe socket.

. To prevent the lower end of the key from passing beyond theoutersurface of the socket, I taper off the lower end of the key to an angleto the axis of the socket shown at g in Fig. 2. To accomplish this Idrill a tapering hole in the bottom of the socket and putin a metalpin,as shown at 9, Fig. 2. The key as it is pressed outward strikesagainst this pin and (No model.)

is prevented from getting out of the socket. The lower end of thematerial of the socket at this point might be filed into a taper; but Iprefer the pin inserted as described. The

drill has akey-seat milled in it, (shown at 71,)

into which the key 0 drops when itis inserted, and the drill is therebyheld from turning when the keeper or square portion at the upper end ofthe drill is broken off, which often happens.

The object of pivoting the key 0, as shown, is to allow it to move back,if, at any time, the operator should put the drill into the socket insuch a manner that the key does not immediately enter the seat h. Insuch case the key moves out of the way, and as soon as the drill isoperated it turns around in the socket until the seat reaches the key,when it drops into it and is held fast therein. If the key has noseat,it is pushed out of the way, and the drill is held by the keeperunless it is broken off, when it is necessary to key-seat the drill orput on a new keeper. The former saves time and expense.

Fig. 3 shows a modification of my invention. The keyis inserted in thesocket and a setscrew jams it tight onto the drill. The key has smallteeth in its side next to the drill. The drill at this point may beflattened or round, as shown in the drawings.

What I claim, and desire to secure by Letters Patent, is

A drill-socket, A, having a movable key, a, pivoted therein for thepurpose of holding the drill when the keeper is broken off,substantially as described.

GEORGE ALBERT LETTER.

iVitnesses:

JAS. LORENZO GAGE, WM. IV. STEWART.

